Field of the Invention
The present invention relates to an apparatus and a method of adhering a belt-shaped tire member to a mold drum.
Background Art
In a process of manufacturing an air tire, a method disclosed in Japanese Patent No. 4,499,803 is proposed as a method of transferring and adhering a belt material to be used for a belt layer from a supply conveyor to a mold drum. In this method, a belt material B1 is placed on a supply conveyor 105 first, and a hand unit 110 waits at a position above the belt material B1 (FIG. 7A). Subsequently, the belt material B1 is held on a lower surface of a pressing plate 132 of the hand unit 110 moving downward from above in a state of being placed on the supply conveyor 105 (FIG. 7B). Subsequently, the supply conveyor 105 rotates and the pressing plate 132 advances in the direction of a mold drum D, whereby the belt material B1 in a state of being sandwiched between the supply conveyor 105 and the pressing plate 132 is fed toward the mold drum D (FIG. 7C). At this time, the mold drum D also rotates. Subsequently, the belt material B1 fed to a position above the mold drum D while being held by the advancing pressing plate 132 is adhered as-is to the rotating mold drum D by the advancing pressing plate 132. When a distal end of the belt material B1 is adhered to the mold drum D by actions described above, the supply conveyor 105, the pressing plate 132, and the mold drum D are stopped. The hand unit 110 then returns to the position above the supply conveyor 105 (FIG. 7D). These actions are repeated until a rear end of the belt material B1 is adhered to the mold drum D.
In the method described above, transferring and adhering actions of the belt material B1 to the mold drum D are stopped while the pressing plate 132 having the belt material B1 adhered thereto returns from a position on the mold drum D to a position above the supply conveyor 105. Therefore, waste of time results. In addition, since a tension applied to the belt material B1 can hardly be maintained uniformly when re-holding the belt material B1, a non-uniform tension arises in the belt material B1 adhered to the mold drum D. This non-uniformity arises in the circumferential direction of the drum at positions corresponding to the number of times of the repetition of the above-described actions, so that degradation of uniformity of the tires as products results.
As a transferring method with reduced waste of time, utilization of an apparatus disclosed in JP-A-2001-079954 is conceivable. This apparatus includes a magnet fixed to the circulating conveyor except for a portion near a supporting shaft on the inner peripheral side. In this apparatus, a belt-shaped material is transferred from one end side to the other end side in association with the circulation of the conveyor without stopping in the midcourse in a state of being stuck to an outer peripheral surface of the conveyor by a magnetic force of the magnet.
However, in this method, since the magnet does not exist at the portion near the supporting shaft on the inner peripheral side of the conveyor, when the distal end of the belt material B1 comes to the position near the supporting shaft of the conveyor, the distal end cannot be held properly and may jump up toward the outer periphery of the conveyor. When the magnetism of the magnet is increased, the conveyor is pressed by the belt-shaped material and the magnet, which are attracting strongly each other. Therefore, a large torque is required for circulating the conveyor and, in addition, the conveyor cannot be circulated smoothly.